I. Introduction
The lithographic gap between the light wavelength and the actual feature sizes is having a prominent impact on the patterns used for layout generation in current manufacturing processes. Various resolution enhancement techniques are applied to obtain faithful printed feature sizes much smaller than the light wavelength [1]. The effectiveness of these techniques is limited, however, to certain geometrical configurations, restricting the set of allowed layout shapes. This fact has contributed to an enormous increase of layout design rules at each technology generation.